Apparatus for treating fusible material



Sept. 2, 1958 M. SIEGEL 2,850,609

APPARATUS FOR TREATING FUSIBLE MATERIAL Filed March 1a, 1956 FIG.2 FIG.3

INVENTOR. Marzz'r; Jz'eye/ "Y iifmi ATTORNEYS United States Patent APPARATUS FOR TREATING FUSIBLE MATERIAL Martin Siegel, Roslyn, N. Y., assignor to Aristocrat Leather Products, Inc., New York, N. Y., a corporation of New Jersey 7 Application March 16, 1956, Serial N 0. 572,030

2 Claims. (Cl. 21910.47)

The present invention relates, in general, to the treatment of fusible materials and, in particular, to an improved apparatus and methods therefor.

It is well known in the art to seal, emboss or otherwise treat fusible or thermoplastic materials through the use of an externally heated die or through the use of high frequency energy for generating heat within the material itself. While it is frequently more desirable to use the latter, or electronic heating apparatus for treating thermoplastic materials, said apparatus nevertheless has the disadvantage, when compared with the use of a directly heated or externally heated die, that the power requirement for high frequency dielectric heating is very much greater than the power requirement for the external heating of the die or of the thermoplastic material.

Therefore, the primary object of the present invention is to obviate the foregoing disadvantages of the prior art and yet to retain the advantages inherent in the use of internally generated heat for sealing, embossing or otherwise treating fusible materials.

Another object is the provision of means and methods for reducing the power required for electronic heating operations. 7

Another object is to increase the capacity of electronic heating devices or to reduce the operating cycles thereof without the necessity of increasing the power requirements thereof.

A further object is the provision of means and methods for reducing the dissipation or transfer of the heat generated in fusible material by an electronic heating apparatus.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawings.

Referring now to the drawings in detail, which illustrate the best modes presently preferred for practicing the invention:

Fig. 1 is a side view of an electronic heating apparatus pursuant to the present invention, illustrated more-or-less in schematic fashion, a portion thereof being shown in section for purposes of illustration;

Fig. 2 is a plan view taken on the line 22 of Fig.

Fig. 3 is a plan view taken on the line 3-3 of Fig.

Fig. 4 is a wiring diagram; and

Fig. 5 is a fragmentary view similar to Fig. 1, illustrating a modification.

Referring now to Figs. 1 to 4 in detail, there is illustrated an electronic heating apparatus 10, pursuant to the present invention, for heating fusible or thermoplastic material, generally indicated by the reference numeral 12. As here shown, provision is made for a press 13 con stituted by a stationary support 14 and a vertically reciprocable ram 16. The support 14 mounts a base plate 18 which is connected as by the conductor 20, to a high frequency electric generator 22.

The ram 16 mounts a plate 24, which is suitably electrically insulated therefrom and which is connected, as

Patented Sept. 2, 1958 by the conductor 26 to the high frequency generator 22. The plates 18 and 24 constitute the electrodes of a high frequency or dielectric heating apparatus, the power thereto being supplied by the high frequency current generator 22.

Pursuant to the present invention, the electrode 24 is provided with an external heating means 28. As here shown, the external heating means 28 is constituted by a die carrier casing 30 provided with an electric heater coil or resistance element 32. The casing 30 is suitably secured to the electrode plate 24, as by the screws 3434. Provision is also made in the electrode plate 24 for the leveling screws 36 which abut against the casing 30 for adjusting the latter to register the die 38 with the work 12.

The casing 30, at its undersurface, mounts or carries the die 38 which is heated by the heater 32. Die 38 may be of any type suitable for its intended use and purpose. For example and not by way of limitation, the die 38 may be an embossing die for embossing the work 12, or it may be a sealing die where portions of the work 12 are to be sealed together, or it may be a combined embossing and sealing die, or the die 38 may have provision to form a tear seal in the work, as in Patent No. 2,710,046 dated June 7, l955, issued to George Markus and Martin Siegel, and assigned to the assignee hereof. In this connection, it will be noted that, as here shown, the work 12 may be constituted by the sheets 40 and 42 of thermoplastic material and, as indicated, the apparatus 10 may be utilized to seal said sheets together, to emboss the upper one of the sheets, to form a tear seal in the upper sheet 40, or for any. combination of these processes, all depending upon the particular type of die 38 which is being used in the apparatus.

Provision is made for a pair of switches 44 and 46 which are operated by an insulation cam member 48 provided on the ram 16, during the downward travel of the ram for engaging the die 38 with the work 12. The switch 44 is a normally open switch in the energizing circuit for the generator 22, and operates when closed to turn on the generator 22, this occurring when the ram 16 has moved the die 38 into engagement with the work 12. The switch 46 is a normally closed switch in circuit with the electric resistance heating element 32, as best seen in Fig. 4. The switch 46 completes the energizing circuit between the heater 32 and its electric power source, indicated at 50-52.

The upper leaf 54 of the switch 44 is provided with a rod 56 of insulation material which passes through an aperture in the lower leaf 58 of the switch 44 and through an aperture in the upper leaf 60 of the switch 46. Consequently, it will be noted that, in the retracted position of the ram 16, as illustrated, the generator 22 is inoperative since its On-Ofi. switch 44 is open, and the energizing circuit for the heating element 32 is closed by the switch 46 for heating the die 38. When the ram 16 moves downwardly to bring the die 38 into engagement with the Work 12, the insulated cam 48 engages the upper leaf 54 of the generator starting switch 44, to close the latter switch, and urges the rod 56 against the lower leaf 62 of the heating element switch 46, for opening the latter switch to de-energize the heating element. Therefore, it will be apparent that, in the retracted condition of the ram 16, the die 38 is being heated by the external heating source constituted by the resistance element 32 and the high frequency generator is inoperative. When the die 38 engages the work 12, the energizing circuit for the external heating element is interrupted and the energizing circuit for the high frequency heating apparatus is completed. The high frequency generator 22 being turned on, power is supplied to the electrodes 24 and 18, and heat is generated, by dielectric action, in the work 12disposed between the electrodes, in the usual manner.

Heretofore, in the case of dielectric heating of work disposed between the electrodes of a high frequency heating apparatus, much of the heat generated within the work was dissipated or transferred into the ambient atmosphere and, through the associated unheated die, into the metallic parts of the press mounting the electrodes of the heating device. However, pursuant to the present invention it will be noted that the die 38, casing 30, and the electrode 24 are all heated by the electric heating element 32, before the start of the dielectric heating operation by the closing of the switch 44, so as to provide heated parts and a heated area about the work 12 when the die engages the work and the electrodes are energized. I have found that the heated die and other heated parts minimize or reduce the transfer of the internally generated heat from the work into the adjacent metallic parts of the press 13 and the heated area about the work 12, resulting from the positioning of the heated parts adjacent the work, materially reduces the loss or dissipation of the internally generated heat into the ambient atmosphere. As a result of the reduction in the heat loss or heat transfer from the work 12, many advantages may be derived from the use of the dielectric heating apparatus of the present invention. For example, the present apparatus requires less power than a conventional dielectric heating apparatus of the same capacity. In the alternative, for the same amount of power as heretofore used in a conventional dielectric heating apparatus of the same capacity, the capacity of the present apparatus can be materially increased by adding additional dies thereto for simultaneously treating additional work. Consequently, the output of a dielectric heating apparatus can be increased without increasing the power required therefor. In addition, I have found that by retaining the same amount of power heretofore required for a dielectric heater of the same capacity, it is possible to greatly reduce the time required for a particular operation. For example, and not by way of limitation, I have found that the time required for a particular embossing operation has ben reduced from approximately six seconds to approximately one and a half seconds, without increasing the radio frequency power supplied to the dielectric heating apparatus, by the use of the external heating means 28 of the present invention. Consequently, it will be apparent that the time cycle of the apparatus is greatly reduced as compared with a similar apparatus of the same capacity and using the same amount of radio frequency energy but not provided with the external heating means 28.

In order to further reduce the possibility of the dissipa- I tion or transfer of the internally generated heat within the work 12, a layer 68 of insulating material may be provided on the electrode plate 18 and the work 12 may be mounted on the insulating layer 68 as illustrated in Fig. 1. This will reduce the heat transfer to the support 14.

In order to eliminate the possibility of feeding radio frequency energy into the A. C. mains used to supply the electric heater 32, the wiring circuit thereof may be provided with the radio frequency filter condensers 64-64, as illustrated in Fig. 4. In addition, provision may be made in said wiring circuit for a thermostat 66 so as to 43 interrupt the energizing circuit for the heater 32 above a predetermined temperature.

Referring now to the modification illustrated in Fig. 5, it will be noted that the electric heating device 32 may be directly incorporated into the electrode 24A so as to eliminate the necessity for a separate casing 30 for the heater illustrated in Fig. l, the die 38A being carried by the electrode 24A. In all other respects the apparatus illustrated in Fig. 5 functions and operates in the same manner as that illustrated in Fig. 1.

The terms die or die means, as used in the appended claims, includes, without limitation, a sealing die, a cutting die, an embossing die, a die to form a tear edge, or any combination thereof.

While I have shown and described the preferred embodiments of my invention, it will be understood that various changes may be made in the idea or principles of the invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. Apparatus of the character described comprising a generator of high frequency electric energy, a base constituted by a first electrode connected to said generator, a second electrode connected to said generator and mounted on a ram for reciprocation relative to said base for generating heat within material mounted by said base, said second electrode having provision to mount a die for said material, a heater for heating the die, cam means mounted on said ram for reciprocal movement therewith, switch means disposed in the path of said cam means, said switch means comprising a normally open start switch for said generator and a normally closed switch in circuit between said external heater and an energizing source therefor, the downward movement of said cam means causing engagement thereof with said switch means whereby to close said start switch and open said external heater switch when said second electrode has moved to said base.

2. Apparatus of the character described comprising a generator of high frequency electric energy, a base constituted by a first electrode connected to said generator, a second electrode connected to said generator and mounted on a ram for reciprocation relative to said base for generating heat within material mounted by said base, said second electrode having provision to mount a die for said material, a heater for heating said die, cam means mounted on said ram for reciprocal movement therewith, switch means disposed in the path of said cam means, the downward movement of said cam means causing engagement thereof with said switch means to activate said high frequency energy source and deactivate said die heater when said electrodes are moved toward each other.

References Cited in the file of this patent UNITED STATES PATENTS Lippman May 29, 1956 Manwaring July 31, 1956 

